ceph/src/boost/libs/statechart/include/boost/statechart/detail/counted_base.hpp

   1 #ifndef BOOST_STATECHART_DETAIL_COUNTED_BASE_HPP_INCLUDED
   2 #define BOOST_STATECHART_DETAIL_COUNTED_BASE_HPP_INCLUDED
   3 //////////////////////////////////////////////////////////////////////////////
   4 // Copyright 2002-2006 Andreas Huber Doenni
   5 // Distributed under the Boost Software License, Version 1.0. (See accompany-
   6 // ing file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   7 //////////////////////////////////////////////////////////////////////////////
   8
   9
  10
  11 #include <boost/detail/atomic_count.hpp>
  12 #include <boost/config.hpp> // BOOST_NO_ARGUMENT_DEPENDENT_LOOKUP
  13
  14
  15
  16 namespace boost
  17 {
  18 namespace statechart
  19 {
  20 namespace detail
  21 {
  22
  23
  24
  25 template< bool NeedsLocking >
  26 struct count_base
  27 {
  28   count_base() : count_( 0 ) {}
  29   mutable boost::detail::atomic_count count_;
  30 };
  31
  32 template<>
  33 struct count_base< false >
  34 {
  35   count_base() : count_( 0 ) {}
  36   mutable long count_;
  37 };
  38
  39 //////////////////////////////////////////////////////////////////////////////
  40 template< bool NeedsLocking = true >
  41 class counted_base : private count_base< NeedsLocking >
  42 {
  43   typedef count_base< NeedsLocking > base_type;
  44   public:
  45     //////////////////////////////////////////////////////////////////////////
  46     bool ref_counted() const
  47     {
  48       return base_type::count_ != 0;
  49     }
  50
  51     long ref_count() const
  52     {
  53       return base_type::count_;
  54     }
  55
  56   protected:
  57     //////////////////////////////////////////////////////////////////////////
  58     counted_base() {}
  59     ~counted_base() {}
  60
  61     // do nothing copy implementation is intentional (the number of
  62     // referencing pointers of the source and the destination is not changed
  63     // through the copy operation)
  64     counted_base( const counted_base & ) : base_type() {}
  65     counted_base & operator=( const counted_base & ) { return *this; }
  66
  67   public:
  68     //////////////////////////////////////////////////////////////////////////
  69     // The following declarations should be private.
  70     // They are only public because many compilers lack template friends.
  71     //////////////////////////////////////////////////////////////////////////
  72     void add_ref() const
  73     {
  74       ++base_type::count_;
  75     }
  76
  77     bool release() const
  78     {
  79       BOOST_ASSERT( base_type::count_ > 0 );
  80       return --base_type::count_ == 0;
  81     }
  82 };
  83
  84
  85
  86 } // namespace detail
  87 } // namespace statechart
  88 } // namespace boost
  89
  90
  91
  92 #endif